1. Field of the Invention
The present invention relates to an electrode structure of a semiconductor device, which is applied to a semiconductor substrate formed of a compound such as GaAs.
2. Description of the Related Art
According to a conventional electrode structure of a semiconductor device using a gallium arsenic (GaAs) substrate, generally, titanium (Ti), platinum (Pt), and gold (Au) are deposited in sequence on the GaAs substrate. For example, an electrode pad of a semiconductor device has this structure.
If, however, the electrode pad has such an electrode structure and the well-known wire bonding is performed, the electrode pad peels off the GaAs substrate the because of tension caused when wires are formed. Since the titanium almost always peels off the GaAs substrate, its adhesiveness to the GaAs substrate is very poor. Thus, a defective in electrode occurs in semiconductor devices having a GaAs substrate, thereby causing the yield to be lowered.